INTRODUCTION 



Wire rope has important applications in industry for holding, 

 towing, and lifting, and much has been done to improve its qual- 

 ity and dependability. It has equal importance in oceanographic 

 work. Deep mooring by the taut- wire technique, coring and 

 dredging, under-water photography, and sampling of water, bot- 

 tom materials, and biological life, are only a few of the oceano- 

 graphic activities which require the use of cables and which pre- 

 sent new and rigorous demands upon the strength, flexibility, and 

 general reliability of the wire used in their construction. These 

 demands increase as oceanographic investigations continue to in- 

 volve greater depths and longer periods of submersion. Whereas 

 in most industrial applications both ends of a cable are firmly se- 

 cured, oceanographic operations require suspension and subse- 

 quent maneuvering of a weight on the end of a line which is capable 

 of stretching and rotating as the load is lowered into the water. 

 The destructive effect of the ocean environment upon cable mate- 

 rial adds to the problem of selecting wire rope of optimum char- 

 acteristics for marine operations. 



The investigation reported here was undertaken to determine 

 which cables, of the many types now available, are most suitable 

 for oceanographic applications. 



FACTORS IN CABLE EFFECTIVENESS 



The basic requirements for any cable are strength and flex- 

 ibility. The cables used in oceanographic operations require spe- 

 cial characteristics in addition to the basic strength necessary to 

 handle heavy loads. Corrosion, magnetic properties, conditions 

 of shock, abrasion, vibration, and extremes of temperature are 

 all potential sources of damage, premature wear, and unsatisfac- 

 tory performance. These hazards must be considered in any 

 choice of marine cable. 



